MSA1000 false disk failures

I have an MSA1000 connected thru FC to an HP-UX 11i N-class. It has fw v4.48.B342 and EMU v1.86. Its got 8 of 146.8G disks.

Our problems is that once in about 2 months or so the disks claim to be dead with orange lights. But once you pull the disk out and let it spin down for a while, on inserting the drive again, it starts rebuilding and everything getting back to normal. The has been going on for almost a year and only once was it a true disk failure compared to 4 of the hoax failures. Functionaly everything else is OK.